Just five races into 2015, attention is already returning to the issue of Jenson Button\'s future.Kimi Raikkonen may be a few months older, but 35-year-old is the oldest driver on the grid.Last year,

Just five races into 2015, attention is already returning to the issue of Jenson Button's future.

Kimi Raikkonen may be a few months older, but 35-year-old is the oldest driver on the grid.

Last year, he survived McLaren's protracted dithering over its driver choice for 2015, but it is believed the British team signed only a one-year extension with the 2009 world champion.

At the same time, the Woking outfit has two drivers knocking loudly on the door - reserve Kevin Magnussen, and the increasingly impressive McLaren junior Stoffel Vandoorne, who is the overwhelming favourite to win this year's GP2 title wearing McLaren colours.

For the moment, however, team boss Eric Boullier is quiet when it comes to 2016.

"There is no plans," he told the BBC, "no discussion so far."

However, he said it would be premature to write off Button, particularly as some have been surprised the veteran Briton is comparing well against Fernando Alonso so far in 2015 - despite a retainer some three times smaller than the Spaniard's.

"People consider Fernando as one of the best drivers and they are right," said Boullier. "But it is underestimating Jenson a little bit.

"Jenson is a great driver and there is a very good working relationship between them. From that balance you can see both are talented enough to match each other and emulate each other a little bit," he added.